Subtract 0.2 J from 7.26 and express the result with correct number of significant figures

Options

A. 7.1
B. 7.06
C. 7
D. None of these

Answer

To solve the problem of subtracting 0.2 J from 7.26 J and expressing the result with the correct number of significant figures, we can follow these steps:

### Step 1: Perform the Subtraction
We start by subtracting 0.2 from 7.26.

\[ 7.26 - 0.2 = 7.06 \]

### Step 2: Determine Significant Figures
Next, we need to determine the number of significant figures in our result. The number 7.26 has 3 significant figures, while 0.2 has 1 significant figure. According to the rules of significant figures in subtraction, the result should be expressed with the same number of decimal places as the number with the least decimal places used in the operation.

- The number 7.26 has two decimal places.
- The number 0.2 has one decimal place.

Since 0.2 has the least decimal places (1 decimal place), our result must also be rounded to 1 decimal place.

### Step 3: Round the Result
Now we round 7.06 to 1 decimal place. The first decimal place in 7.06 is 0, and the second decimal place is 6. Since the second decimal digit (6) is greater than 5, we round up the first decimal place (0) by 1.

Thus, rounding 7.06 gives us:

\[ 7.1 \]

### Final Answer
The final result of the subtraction, expressed with the correct number of significant figures, is:

\[ \text{Answer: } 7.1 \, \text{J} \]

---